Field of the Invention
The invention relates in general to an image processing method and an image processing device, and more particularly to a fisheye image processing method and a fisheye image processing device.
Description of the Related Art
With the progressive development of image technologies, various image capturing devices are continuously innovated. Viewing angles of some fisheye lenses may even exceed 180 degrees. By stitching two fisheye images respectively captured by a front fisheye lens and a rear fisheye lens both having a viewing angle greater than 180 degrees, a panoramic image is generated.
FIG. 1 shows a schematic diagram of a conventional image process method. First, an image processing unit receives a merged image 820 formed by combining two fisheye images 811 and 812 respectively generated by a front fisheye lens and a rear fisheye lens both having a viewing angle greater than 180 degrees. The image processing unit divides the merged image 820 into fisheye images 811 and 812, performs an equirectangular projection on the fisheye images 811 and 812 to obtain equirectangular images 831 and 832. The image processing unit further swaps positions of a left-half image 832a and a right-half image 832b of the equirectangular image 832 to obtain another equirectangular image 833. Next, the image processing unit stitches the equirectangular image 831 and the equirectangular image 833 along a first stitch line L81 and a second stitch line L82 to obtain a panoramic image 840.
FIG. 2 shows a panoramic spherical image 850 obtained from converting the panoramic image 840 in FIG. 1. In FIG. 2, an enlarged view of the panoramic image 850 corresponds to a seam S1 of the panoramic image 840 located at a high altitude. However, as shown in FIG. 2, in the panoramic spherical image 850, noticeable discontinuity exists at the seam S1, which severely affects the image quality.